In order to meet the requirements of high reliability and low latency in the 5G network environment， and reduce the resource consumption of network bandwidth at the same time， a Service Function Chain （SFC） deployment method based on node comprehensive importance ranking for traffic and reliability optimization was proposed. Firstly， Virtualized Network Function （VNF） was aggregated based on the rate of traffic change， which reduced the deployed physical nodes and improved link reliability. Secondly， node comprehensive importance was defined by the degree， reliability， comprehensive delay and link hop account of the node in order to sort the physical nodes. Then， the VNFs were mapped to the underlying physical nodes in turn. At the same time， by restricting the number of links， the “ping-pong effect” was reduced and the traffic was optimized. Finally， the virtual link was mapped through k-shortest path algorithm to complete the deployment of the entire SFC. Compared with the original aggregation method， the proposed method has the SFC reliability improved by 2%， the end-to-end delay of SFC reduced by 22%， the bandwidth overhead reduced by 29%， and the average long-term revenue-to-cost ratio increased by 16%. Experimental results show that the proposed method can effectively improve the link reliability， reduce end-to-end delay and bandwidth resource consumption， and play a good optimization effect.

Aiming at the problem that most mapping algorithms based on virtual Software Defined Network （vSDN） do not fully consider the correlation between nodes and links， a vSDN mapping algorithm based on network topology segmentation and clustering analysis was proposed. Firstly， the complexity of physical network was reduced by the topology segmentation method based on the shortest hop count. Then， the request acceptance rate of mapping algorithm was improved by the clustering analysis method based on node topology and resource attributes. Finally， the nodes that do not meet the link requirements were remapped， by dispersing the link constraints to the bandwidth resources of nodes and the degrees of nodes to perform the consideration with constraints， so that the mapping process between nodes and links was optimized. Experimental results show that， the proposed algorithm can effectively improves the request acceptance rate of virtual network mapping algorithm based on Software Defined Network （SDN） architecture in physical networks with low connectivity probability.